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Kolter M, Koszinowski K. Formation of Transient Anionic Metal Clusters in Palladium/Diene-Catalyzed Cross-Coupling Reactions. Chemistry 2019; 25:13376-13384. [PMID: 31335999 PMCID: PMC7687115 DOI: 10.1002/chem.201902610] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 07/11/2019] [Indexed: 12/30/2022]
Abstract
Despite their considerable practical value, palladium/1,3-diene-catalyzed cross-coupling reactions between Grignard reagents RMgCl and alkyl halides AlkylX remain mechanistically poorly understood. Herein, we probe the intermediates formed in these reactions by a combination of electrospray-ionization mass spectrometry, UV/Vis spectroscopy, and NMR spectroscopy. According to our results and in line with previous hypotheses, the first step of the catalytic cycle brings about transmetalation to afford organopalladate anions. These organopalladate anions apparently undergo SN 2-type reactions with the AlkylX coupling partner. The resulting neutral complexes then release the cross-coupling products by reductive elimination. In gas-phase fragmentation experiments, the occurrence of reductive eliminations was observed for anionic analogues of the neutral complexes. Although the actual catalytic cycle is supposed to involve chiefly mononuclear palladium species, anionic palladium nanoclusters [Pdn R(DE)n ]- , (n=2, 4, 6; DE=diene) were also observed. At short reaction times, the dinuclear complexes usually predominated, whereas at longer times the tetra- and hexanuclear clusters became relatively more abundant. In parallel, the formation of palladium black pointed to continued aggregation processes. Thus, the present study directly shows dynamic behavior of the palladium/diene catalyst system and degradation of the active catalyst with increasing reaction time.
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Affiliation(s)
- Marlene Kolter
- Institut für Organische und Biomolekulare ChemieUniversität GöttingenTammannstrasse 237077GöttingenGermany
| | - Konrad Koszinowski
- Institut für Organische und Biomolekulare ChemieUniversität GöttingenTammannstrasse 237077GöttingenGermany
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Bailey WD, Phearman AS, Luconi L, Rossin A, Yakhvarov DG, D'Accolti L, Flowers SE, Kaminsky W, Kemp RA, Giambastiani G, Goldberg KI. Hydrogenolysis of Dinuclear PCN R Ligated Pd II μ-Hydroxides and Their Mononuclear Pd II Hydroxide Analogues. Chemistry 2019; 25:9920-9929. [PMID: 31090244 DOI: 10.1002/chem.201900507] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 05/05/2019] [Indexed: 11/11/2022]
Abstract
The hydrogenolysis of mono- and dinuclear PdII hydroxides was investigated both experimentally and computationally. It was found that the dinuclear μ-hydroxide complexes {[(PCNR )Pd]2 (μ-OH)}(OTf) (PCNH =1-[3-[(di-tert-butylphosphino)methyl]phenyl]-1H-pyrazole; PCNMe =1-[3-[(di-tert-butylphosphino)methyl]phenyl]-5-methyl-1H-pyrazole) react with H2 to form the analogous dinuclear hydride species {[(PCNR )Pd]2 (μ-H)}(OTf). The dinuclear μ-hydride complexes were fully characterized, and are rare examples of structurally characterized unsupported singly bridged μ-H PdII dimers. The {[(PCNMe )Pd]2 (μ-OH)}(OTf) hydrogenolysis mechanism was investigated through experiments and computations. The hydrogenolysis of the mononuclear complex (PCNH )Pd-OH resulted in a mixed ligand dinuclear species [(PCNH )Pd](μ-H)[(PCC)Pd] (PCC=a dianionic version of PCNH bound through phosphorus P, aryl C, and pyrazole C atoms) generated from initial ligand "rollover" C-H activation. Further exposure to H2 yields the bisphosphine Pd0 complex Pd[(H)PCNH ]2 . When the ligand was protected at the pyrazole 5-position in the (PCNMe )Pd-OH complex, no hydride formed under the same conditions; the reaction proceeded directly to the bisphosphine Pd0 complex Pd[(H)PCNMe ]2 . Reaction mechanisms for the hydrogenolysis of the monomeric and dimeric hydroxides are proposed.
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Affiliation(s)
- Wilson D Bailey
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington, 98195-1700, USA
| | - Alexander S Phearman
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Lapo Luconi
- Institute of Chemistry of Organometallic Compounds, ICCOM-CNR and Consorzio INSTM, Via Madonna del Piano, 10-50019 Sesto Fiorentino, Florence, Italy
| | - Andrea Rossin
- Institute of Chemistry of Organometallic Compounds, ICCOM-CNR and Consorzio INSTM, Via Madonna del Piano, 10-50019 Sesto Fiorentino, Florence, Italy
| | - Dmitry G Yakhvarov
- Kazan Federal University, 420008, Kazan, Russian Federation.,Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 420008, Kazan, Russian Federation
| | - Lucia D'Accolti
- Università di Bari "A. Moro", Via Orabona 4, 70126, Bari, Italy
| | - Sarah E Flowers
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington, 98195-1700, USA
| | - Werner Kaminsky
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington, 98195-1700, USA
| | - Richard A Kemp
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico, 87131, USA.,Advanced Materials Laboratory, Sandia National Laboratories, Albuquerque, New Mexico, 87106, USA
| | - Giuliano Giambastiani
- Institute of Chemistry of Organometallic Compounds, ICCOM-CNR and Consorzio INSTM, Via Madonna del Piano, 10-50019 Sesto Fiorentino, Florence, Italy.,Kazan Federal University, 420008, Kazan, Russian Federation.,Institute of Chemistry and Processes for Energy, Environment and Health (ICPEES), UMR 7515 CNRS-University of Strasbourg (UdS), 25, rue Becquerel, 67087, Strasbourg Cedex 02, France
| | - Karen I Goldberg
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington, 98195-1700, USA.,Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
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Murahashi T, Inoue R, Usui K, Ogoshi S. Square Tetrapalladium Sheet Sandwich Complexes: Cyclononatetraenyl as a Versatile Face-Capping Ligand. J Am Chem Soc 2009; 131:9888-9. [DOI: 10.1021/ja903679f] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tetsuro Murahashi
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, and PRESTO, Japan Science and Technology Agency (JST), Suita, Osaka 565-0871, Japan
| | - Ryou Inoue
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, and PRESTO, Japan Science and Technology Agency (JST), Suita, Osaka 565-0871, Japan
| | - Kentaro Usui
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, and PRESTO, Japan Science and Technology Agency (JST), Suita, Osaka 565-0871, Japan
| | - Sensuke Ogoshi
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, and PRESTO, Japan Science and Technology Agency (JST), Suita, Osaka 565-0871, Japan
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Mezei G, Zaleski CM, Pecoraro VL. Structural and Functional Evolution of Metallacrowns. Chem Rev 2007; 107:4933-5003. [PMID: 17999555 DOI: 10.1021/cr078200h] [Citation(s) in RCA: 433] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gellert Mezei
- Department of Chemistry, Willard H. Dow Laboratories, University of Michigan, Ann Arbor, Michigan 48108-1005, and Department of Chemistry, Franklin Science Center, Shippensburg University, Shippensburg, Pennsylvania 17257-2200
| | - Curtis M. Zaleski
- Department of Chemistry, Willard H. Dow Laboratories, University of Michigan, Ann Arbor, Michigan 48108-1005, and Department of Chemistry, Franklin Science Center, Shippensburg University, Shippensburg, Pennsylvania 17257-2200
| | - Vincent L. Pecoraro
- Department of Chemistry, Willard H. Dow Laboratories, University of Michigan, Ann Arbor, Michigan 48108-1005, and Department of Chemistry, Franklin Science Center, Shippensburg University, Shippensburg, Pennsylvania 17257-2200
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Cugnet C, Lucas D, Collange E, Hanquet B, Vallat A, Mugnier Y, Soldera A, Harvey PD. Generation, Characterization, and Electrochemical Behavior of the Palladium–Hydride Cluster [Pd3(dppm)3(μ3-CO)(μ3-H)]+ (dppm=Bis(diphenylphosphinomethane). Chemistry 2007; 13:5338-46. [PMID: 17455171 DOI: 10.1002/chem.200700069] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Addition of formate on the dicationic cluster [Pd(3)(dppm)(3)(mu(3)-CO)](2+) (dppm=bis(diphenylphosphinomethane) affords quantitatively the hydride cluster [Pd(3)(dppm)(3)(mu(3)-CO)(mu(3)-H)](+). This new palladium-hydride cluster has been characterised by (1)H NMR, (31)P NMR and UV/Vis spectroscopy and MALDI-TOF mass spectrometry. The unambiguous identification of the capping hydride was made from (2)H NMR spectroscopy by using DCO(2) (-) as starting material. The mechanism of the hydride complex formation was investigated by UV/Vis stopped-flow methods. The kinetic data are consistent with a two-step process involving: 1) host-guest interactions between HCO(2) (-) and [Pd(3)(dppm)(3)(mu(3)-CO)](2+) and 2) a reductive elimination of CO(2). Two alternatives routes to the hydride complex were also examined : 1) hydride transfer from NaBH(4) to [Pd(3)(dppm)(3)(mu(3)-CO)](2+) and 2) electrochemical reduction of [Pd(3)(dppm)(3)(mu(3)-CO)](2+) to [Pd(3)(dppm)(3)(mu(3)-CO)](0) followed by an addition of one equivalent of H(+). Based on cyclic voltammetry, evidence for a dual mechanism (ECE and EEC; E=electrochemical (one-electron transfer), C=chemical (hydride dissociation)) for the two-electron reduction of [Pd(3)(dppm)(3)(mu(3)-CO)(mu(3)-H)](+) to [Pd(3)(dppm)(3)(mu(3)-CO)](0) is provided, corroborated by digital simulation of the experimental results. Geometry optimisations of the [Pd(3)(H(2)PCH(2)PH(2))(3)(mu(3)-CO)(mu(3)-H)](n) model clusters were performed by using DFT at the B3 LYP level. Upon one-electron reductions, the Pd--Pd distance increases from a formal single bond (n=+1), to partially bonding (n=0), to weak metal-metal interactions (n=-1), while the Pd--H bond length remains relatively the same.
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Affiliation(s)
- Cyril Cugnet
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR CNRS 5260, Faculté des Sciences Mirande, Université de Bourgogne, 9 avenue Alain Savary, 21000 Dijon, France
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Evrard D, Groison K, Mugnier Y, Harvey PD. The Pd4(dppm)4(H)22+ Cluster: A Precatalyst for the Homogeneous Hydrogenation of Alkynes. Inorg Chem 2003; 43:790-6. [PMID: 14731043 DOI: 10.1021/ic0347992] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The catalytic properties of the title cluster toward the homogeneous hydrogenation of phenylacetylene, diphenylethyne and phenyl-1-propyne have been investigated as a function of temperature, pressure, solvents, substrate and cluster concentrations, and counterions. The title cluster is a precatalyst that exhibits a good catalytic activity under mild conditions (1 atm of H(2) at 20 degrees C) for the hydrogenation of alkynes and alkenes. For the alkyne substrates, the turnover frequencies (tof's) range between 200 and 500 h(-)(1), and the product distribution varies as: cis-products, 75-90%; trans-products; 0-8% after 3 h of reaction. Based on the graphs -d[substrate]/dt vs [Pd(4)](1/2), the mechanism indicates a cluster dissociation into two dimers (presumably of the type Pd(2)(dppm)(2)(H)(solvent)(+)). The variations of tof (or -d[substrate]/dt) as a function of [substrate] and pressure of H(2) are linear. At 1600 psi of H(2), the tof can reach 2500-3000 h(-)(1) (in THF). The tof also increases with temperature reaching a maximum at approximately 35 degrees C (tof: 1000-1300 h(-)(1)), but at higher temperatures cluster decomposition begins to occur, leading to a rapid decrease in rates of catalysis. At 50 degrees C, no catalysis is observed. The hydrogenation reaction can be stopped at the corresponding cis-alkenes with approximately 95% yields, depending on the substrate and experimental conditions used. The tof's also vary with the solvent, where stronger coordinating solvent molecules give higher tof's. In addition, the tof's do not change with the nature of the counterion, which acts as "spectator" in the catalysis.
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Affiliation(s)
- David Evrard
- Contribution from the Laboratoire de Synthèse et d'Electrosynthèse Organométalliques, (LSEO-CNRS UMR 2595), Faculté des Sciences Gabriel, Université de Bourgogne, 6 Boulevard Gabriel, 21000 Dijon, France
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